package main
import (
    "fmt"
    "math"
)
type Rec struct {
    width,height float32
}

type Circle struct {
    radius float64
}

func (r Rec) area() float32{
    return r.height*r.width
}

func (c Circle) area() float64{
    return math.Pi*math.Pow(c.radius,2)
}

func main() {
    r1:=Rec{3,4}
    r2:=Rec{5,6}
    c1:=Circle{1}
    c2:=Circle{2}

    fmt.Println("area r1:",r1.area())
    fmt.Println("area r2:",r2.area())
    fmt.Println("c1:",c1.area())
    fmt.Println("c2:",c2.area())
}
